Vehicle assembly line-side heat activation of a “ready-to-install” window fixing adhesive for attachment of a vehicle window to a vehicle

ABSTRACT

A method of preparing a vehicle panel assembly for attaching the panel to a vehicle is disclosed which provides a “ready-to-install” panel assembly. The panel assembly includes first and second spaced sides, with the bead of heat activated adhesive provided on the second side of the panel. The panel and bead are heated preferably by applying shortwave and longwave infrared radiation, with the shortwave infrared radiation being applied to an adhesive free side of the panel to heat the panel and, thereby, indirectly heat the bead of the heat activated adhesive. The longwave infrared radiation is applied to the adhesive side of the panel to directly heat the bead and thereby activate the adhesive. The ready-to-install adhesive may be applied on or adjacent to a gasket, such as a polyvinyl chloride (PVC) molding, a urethane molding, or the like. Optionally, either during or after heating, the substrate is cooled in order to ease handling of the panel assembly after the bead of adhesive is activate and ready for installation.

This is a continuation-in-part of pending patent application Ser. No.09/024,226, filed Feb. 17, 1998, by Applicants Douglas R. Swanson, DavidE. Nestell, and Niall R. Lynam, which is incorporated herein in itsentirety by reference.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to vehicle panel assemblies and, moreparticularly, to vehicle panel assemblies which are mounted to a vehiclewith an adhesive.

Conventional window assemblies are mounted to the vehicle body by anadhesive and often in combination with one or more fasteners which aremounted on the window panel or are embedded in a gasket which has beenpreviously extruded or molded on to the window panel. The adhesive oftenprovides the primary attachment to the vehicle and is applied to thesurface of the panel, for example by extrusion, after priming of thesubstrate surface (typically a glass substrate) and/or the vehicle body(typically metal or a composite material). The window assembly is thenpressed against the mounting flange or decking of the vehicle body towhich the adhesive adheres after curing. Heretofore, these adhesiveshave been moisture cured, for example the moisture cure BETASEAL™ brandadhesive available from Essex Specialty Products of Auburn Hills, Mich.These moisture cure urethane adhesives, however, are currently appliedat the vehicle assembly line and require either robotic application orhand application. Furthermore, the moisture cure adhesives requirerelatively long cure times-these adhesives typically take on the orderof 120 minutes to cure sufficiently to develop the required “decking”strength to hold the window assembly in place. Consequently, the windowassemblies installed in this manner may require temporary support whilemoving along the assembly line. Furthermore, the full strength of theadhesive requires a cure of about 24 to 72 hours, depending onenvironmental conditions. In addition, these cure periods are sensitiveto the surrounding environment. Where the manufacturing plant is locatedin an area having low humidity, the cure time is significantly longerthan in an area having high humidity. Consequently, standardizing suchinstallations is difficult.

In addition to the relatively long cure time, the chemicals forming theadhesive and the adhesive primers require special handling. The adhesivemust be contained in a very low moisture or moisture-free environmentbefore application onto the glass panel to avoid premature curing.Furthermore, the adhesive and primer chemicals require special clean-upprocedures and inventorying to assure full effectiveness of theadhesive. Moreover, these chemicals require proper ventilation, and thepersonnel handling the chemicals require protective gear. Consequently,in-vehicle-plant applications are labor intensive, increase assemblyline-time, potentially increase the frequency of down-time when theadhesive is improperly applied, for example when the adhesive is drippedon other areas of the vehicle, and are, therefore, costly.

More recently, proposals have been made to control the curing process ofthe adhesive by covering the adhesive with a barrier film which is thensubsequently peeled off the bead at the assembly line to allowinstallation and curing. One such example is disclosed in U.S. Pat. No.4,933,032 to Kunert. Kunert '032 also proposes the use of heat orirradiation to actuate a multi-component polyurethane adhesive, whichcontains an initiating or reaction component in inactivated form, forexample in the form of micro-capsules, which are activated by the heator irradiation before assembly of the glazing. While the removablebarrier films and multi-component polyurethane adhesive theoreticallyremove the adhesive application process from the assembly line, numerousproblems still remain. The extrusion and film application process iscomplicated, and the film can be vulnerable to tearing or damage duringtransportation. Furthermore, these films still require removal anddisposal. Moreover, the barrier film must be accurately placed,otherwise, the exposed portions of the adhesive are prematurely curedand may be ineffective as a bonding agent.

The recent trend in vehicles is to produce a stream line or aerodynamicvehicle with larger windows to improve visibility. As a result thewindow assemblies often require compound curvatures. These compoundcurvatures make it hard to heat the panel uniformly. Furthermore, newerwindow panels include laminated substrates, moldings, and attachmentswhich tend to degrade when subject to high temperatures. In order toheat such micro-capsule-containing adhesives over a period of timeconsistent with in-line processing, relatively high energy is required.In addition to possible degradation of the panel substrate, of themoldings, and of the attachments, the bead of adhesive is also subjectto degradation if overheated. Perhaps for these and other reasons,heretofore, no “ready-to-install” window or panel assemblies have beensuccessfully made or commercialized.

Consequently, there is a need for a “ready to install” panel assembly,for example a modular window, which can be quickly installed or “decked”in a vehicle or the like in an assembly line. Preferably, the modularwindow can be preassembled with an adhesive already applied at alocation remote from a vehicle assembly plant to eliminate additionalmanufacturing time at the assembly line, handling of extra materials,on-line purging, which is required to eliminate unused portions of themoisture cured urethane in the dispenser nozzle, handling of chemistryin the vehicle manufacturing plant, including the adhesives and adhesiveprimers, and humidity control equipment and yet can be “decked” with theadhesive which is not activated until just prior to installation andwhich develops sufficient decking strength to hold the modular window inplace.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a method of preparing avehicle panel assembly for attaching the panel assembly to a vehicle.The vehicle panel assembly includes a substrate and a bead ofready-to-install heat activated adhesive. The substrate includes firstand second sides. The bead of heat activated adhesive is applied to thesecond side of the panel. The panel is prepared by heating the firstside of the substrate and by heating the outer skin portion of the beadsuch that the core portion of the bead reaches its activationtemperature. In addition, after heating, the panel assembly is cooled topermit manual handling of the panel assembly.

In preferred forms, the panel assembly is cooled by directing air onto aportion of the substrate to cool the substrate to permit handling of thevehicle panel assembly. For example, the panel assembly may be cooled byblowing a gaseous stream onto the peripheral portion of the substratepreferably at an angle in a range of approximately 5° to 90°. Forexample, the gaseous stream may include air or an inert gas, such asargon or nitrogen or the like. In further forms, the gaseous stream islocalized on the peripheral portion of the substrate to cool thesubstrate, for example by blowing the gaseous stream on the peripheralportion with a knife edge blower.

In other forms, the method of preparing the vehicle panel assemblyfurther includes balancing the heating and the cooling to ensure thatthe central core portion of the bead at least reaches its heatactivation temperature while cooling the substrate below 250° F. Morepreferably, the heating and cooling is balanced to ensure that thecentral core portion of the bead at least reaches its heat activationtemperature while cooling the substrate below 175° F. Most preferably,the heating and cooling is balanced such that the central core portionof the bead at least reaches its heat activation temperature whilecooling the substrate below 120° F. Preferably, the substrate is cooledto a desired temperature within fifteen minutes or less after heating,more preferably within about nine minutes or less after heating, andmost preferably less than two minutes after heating. In addition, themethod preferably includes balancing the heat on the first side and theheat on the second side to heat the central core portion to at least aheat activation temperature in a range of about 50° C. to 160° C. whilemaintaining an outer skin surface temperature at least no more thanabout 40° C. greater than the central core portion temperature andcooling substrate temperature below 120° F. within a period of aboutfifteen minutes or less after heating.

In preferred forms, the heating of the outer skin portion includesheating with longwave infrared radiation, for example with longwaveinfrared radiation with a thermal mass temperature in a range of about450° F. to about 900° F. The first side of the substrate is preferablyheated with shortwave infrared radiation.

In other forms, the cooling is initiated after the adhesive has reacheda heat activation temperature.

According to another aspect of the invention, the vehicle panel includesa substrate and a bead of heat activated adhesive. The substrate hasfirst and second sides and a peripheral portion, with the peripheralportion including a gasket which extends over at least a portion of thesecond side of the substrate. The bead of ready-to-install heatactivated adhesive is applied to the gasket. In this aspect, the methodof preparing the panel assembly includes heating the first side of thesubstrate adjacent gasket whereby the substrate heats the gasket to heatthe interface portion of the bead and heating outer skin portion of thebead to thereby heat the central core portion of the bead and activatethe ready-to-install heat activated adhesive.

In further aspects, the method includes cooling the substrate afterheating the first side of the substrate and the outer skin portion ofthe bead. In one form, the substrate is cooled after theready-to-install heat activated adhesive is activated.

According to yet another form of the invention, a method for preparing avehicle panel assembly for attaching to a vehicle includes heating thevehicle panel substrate with a shortwave radiation source therebyheating the bead with a substrate through the bead's interface portionand heating the bead with a source of longwave infrared radiationwhereby the core of the bead at least reaches an activation temperature.The method further includes cooling the substrate after heating the beadthereby permitting handling of the vehicle panel assembly after the beadof adhesive is activated.

In further forms, the cooling may be initiated after the core of thebead has reached its activation temperature, with the substrate beingcooled to a desired temperature within 15 minutes or less after coolingis initiated, more preferably with the substrate being cooled within 9minutes or less after cooling is initiated, and most preferably with thesubstrate being cooled within 2 minutes or less after cooling isinitiated.

In other forms, the substrate is heated by positioning at least oneheating shortwave infrared emitting lamp spaced from the first side ofthe substrate and aligning the lamp with the central axis. However, thelamps may be offset from the central axis less than twenty-four inches,more preferably less than twelve inches and most preferably less thanone inch from central axis. The lamp is preferably spaced less thantwenty-four inches from the first side of the substrate, morepreferably, less than twelve inches, and most preferably less than threeinches from the first side of the substrate.

In further forms, the bead is heated by positioning the source oflongwave radiation spaced from the second side of the substrate, forexample, preferably less than twenty-four inches from the second side ofthe substrate, more preferably less than twelve inches from the secondside of the substrate and most preferably less than three inches fromthe second side of the substrate. Further, the source of longwaveradiation is preferably aligned with the central axis of the bead.However, similar to the shortwave radiation source, the longwaveradiation source can be offset from the central axis less thantwenty-four inches, more preferably less than twelve inches, and mostpreferably less than one inch from the central axis.

The improved method disclosed herein provides a “ready-to-install” panelassembly, which is particularly suitable for window assemblies. Thepanel assembly is preassembled with a bead of heat activated adhesiveextruded or otherwise applied on a second side of the panel substrate.The bead of adhesive is activated by the application of longwave andshortwave infrared radiation which are respectively applied to the beadof adhesive and to an opposed side of the panel substrate, whichindirectly heats the bead. The panel substrate and other components,such as molded gaskets and the like, are protected from the shortwaveinfrared radiation by localizing the shortwave infrared radiation on adiscrete portion of the first side of the substrate panel which isaligned with the bead of adhesive. In this manner, the bead of adhesiveis quickly and uniformly heated without the associated degradation whichoften occurs with high energy heating. Further, the panel assembly iscooled to permit manual handling of the panel assembly soon after theassembly has been heated and the adhesive has been activated.

These and other objects, advantages, and purposes and features of theinvention will become more apparent form a study of the drawings,specification, and claims which follow.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective schematic view of a heater assembly of thepresent invention positioned along a conveyor which transports panelassemblies to be heated;

FIG. 2 is a cross-section of the heater assembly taken along line II—IIof FIG. 1 including a first embodiment of a heat localizer;

FIG. 2A is an enlarged fragmentary view of a peripheral portion of oneof the panel assemblies to be heated;

FIG. 2B is an enlarged fragmentary view similar to FIG. 2A illustratingthe panel assembly installed in an opening of a vehicle;

FIG. 2C is a cross-section similar to FIG. 2 illustrating a secondembodiment of a heat localizer;

FIG. 3A is a plan view of a multi-stage heater assembly arrangement ofthe present invention aligned along an assembly line conveyor;

FIG. 3B is a plan view of a second embodiment of a multi-stage heaterarrangement of the present invention positioned adjacent an assemblyline conveyor;

FIG. 4 is a plan view of a preferred embodiment of the heater assemblyof present invention positioned in-line for heating panel assembliestransported on a conveyor;

FIG. 5 is a side elevation of the preferred heater assembly of FIG. 4;

FIG. 6 is an end elevation of the preferred heater assembly of FIG. 4;

FIG. 7 is an end elevation view of a third preferred embodiment of aheater assembly of the present invention positioned along a conveyorwhich transport panel assemblies to be heated;

FIG. 8 is an enlarged section view of a peripheral portion of one of thepanel assemblies to be heated by the heater assembly of FIG. 7;

FIG. 9 is an enlarged cross-section view similar to FIG. 8 illustratingthe positions of a shortwave infrared emitting lamp of the heaterassembly of FIG. 7;

FIG. 10 is an enlarged cross-section view similar to FIG. 9 illustratinga second embodiment of the panel assembly to be heated by the heaterassembly of FIG. 7;

FIG. 10A is an enlarged cross-section view similar to FIG. 9illustrating a third embodiment of the panel assembly to be heated bythe heater assembly of FIG. 7;

FIG. 11 is a partial fragmentary perspective of a heat localizer orshield of the heater assembly of FIG. 7;

FIG. 12 is a plan view of shortwave heat emitting lamps of the heaterassembly of FIG. 7;

FIG. 13 is a graph of the cooling profiles of a glass panel heated bythe heater assemblies of the present invention illustrating the effectof cooling the peripheral portion of the panel assembly after heating;

FIG. 14 is a graph of the temperature profile of a bead of heatactivated adhesive of the panel assembly during heating;

FIG. 15 is a graph of a temperature profile of the various components ofthe panel assembly during heating and during cooling; and

FIG. 16 is a plan view of third embodiment of a multi-stage heaterassembly arrangement of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2, 2A and 2B, a panel assembly 10, for example amodular window assembly, which is heated by the apparatus and method ofthe present invention includes a substrate panel or sheet 12, which maycomprise plastic or glass, preferably substantially transparent glass,for example tempered, laminated, or glass which is otherwisestrengthened using conventional techniques. Furthermore, panel 12 maycomprise a multi-laminate panel, for example, of plastic and glasssheets. In addition, panel 12 may comprise a large window, such as awindow having a surface area of at least about 250 square inches or suchas a window with a surface area of at least about 500 square inches.Optionally, panel 12 may be a curved panel (such as a curved panelhaving a compound curvature) with a concave surface on which is disposedthe ready-to-install adhesive and on which are disposed other heatvulnerable attachments, such as polymeric gaskets, studs, bezels, andthe like. Alternately, panel assembly 10 can be a decorative assemblywith panel 12 being translucent or opaque instead of transparent. Panel12 has two substantially parallel sides or surfaces 14 and 16 and aperipheral edge 18. Panel 12 may include an opaque, preferably black,frit layer which extends around peripheral edge 18 and, optionally, isencapsulated with a molded member, for example a polymeric gasket 20 onat least one side 14 or 16 of panel 12.

In the illustrated embodiment, panel 12 includes a three sided polymericgasket molded thereon. Thus, gasket 20 extends around three (3) sides ofpanel 12, namely, surfaces 14, 16 and edge 18. It should also beunderstood that panel 12 may be free of any gasket or may include asingle sided or two sided gasket. Gasket 20 may be formed using avariety of techniques, including reaction injection molding (RIM) ofthermosetting polymeric material, such as polyurethane, or athermoplastic polymeric material which, for example, is injection moldedsuch as polyvinyl chloride (PVC), a thermoplastic urethane, or athermoplastic elastomer (including an ethylene-styrene interpolymerformed from a melt-processible, low halogen free polymer resin material,such as a resin based on polyolefin and produced using a metallocenecatalyst and having a durometer within a range of about 30 to 110 on theShore A scale, more preferably about 65 to 95 Shore A, and mostpreferably 65 to 85 Shore A, for example, one preferred form of anethylene-styrene interpolymer is available from DOW Chemical, Freeport,Tex., and which, preferably, utilizes DOW's INSITE single-catalysttechnology, wherein depending on the amount of styrene incorporated, thesolid state of the polymer can exhibit a variety of structures anddurometer hardnesses, including semi-crystalline and amorphous rubbersuch as described in pending U.S. patent application entitled VEHICULARWINDOW ASSEMBLY, filed by Qihua Xu and David E. Nestell, now U.S. Pat.No. 6,089,646, and assigned to Donnelly Corp. of Holland, Mich., thedisclosure of which is incorporated herein by reference in itsentirety), and other applications, such as extrusion or post attachmentgrommets. In addition, gasket 20 may include one or more fasteners (notshown) embedded in the gasket or secured to the panel adjacent thegasket for securing components to panel assembly 10 or securing panelassembly 10 to the vehicle or the like.

Referring to FIG. 2A, a bead 26 of a heat activated adhesive is extrudedor otherwise applied, including post-applied, onto the peripheralportion of the inside surface 16 of panel 18. In the illustratedembodiment, bead 26 includes a generally quadrilateral-shaped crosssection with a wide base 30 defining an interface portion or region anda side 31 defining a generally outer extremity portion or region, whichis formed by converging sides 32 and 34 such as shown in FIG. 2A. Sides31, 32 and 34 define a bead skin or outer surface portion or region.Intermediate sides 31, 32 and 34 and base 30 is a central portion orregion or core 36. It should be noted that bead 26 may also be dispensedor otherwise applied on a gasketed portion of panel 12 and may assumeother shapes, with the apparatus and method of this invention beingequally suitable for activating the adhesive bead in either position.

Adhesive bead 26 is preferably extruded or otherwise applied onto panel12 at a “just-in-time” plant close to but a distance from the vehicleproduction plant for a “ready-to-install” and/or “sequenced”installation. Consequently, when panel assembly 10 is transported, panelassembly 10 is preferably transported with the adhesive bead positionedor orientated face down so that adhesive bead 26 will be protected bysubstrate panel 12 during transportation. When delivered to the vehicleassembly plant, panel assembly 10 is heated by a heater assembly 50. Asbest seen in FIG. 2B, a second embodiment 26′ of heat activated adhesivebead is shown. Bead 26′ includes a generally triangular-shaped crosssection with a wide base 30′ defining an interface portion or region anda generally pointed outer extremity portion or region 31′, which isformed by converging sides 32′ and 34′. Outer extremity 31′ and sides32′ and 34′ define a bead skin or outer surface portion or region ofbead 26′, with a central core portion 36′ being defined between sides32′ and 34′ and between outer extremity 31′ and interface portion 30′.After heating, panel assembly 10 is installed in an opening 40 of avehicle, and adhesive bead 26′ is compressed against a mounting flangeor deck 42, which extends around opening 40 to adhere panel assembly 10to the vehicle body, with the adhesive characteristics of adhesive bead26′ having been activated by the heater assembly 50 and method ofheating, each of which will be more fully described below.

Referring to FIG. 1, heater assembly 50 of the present invention isshown positioned along a conveyor 52 which transports panel assemblies10 for installation in a vehicle or the like. Conveyor 52 is ofconventional design and includes spaced apart conveyor belts or chains52 a and 52 b, which support panel assemblies 10 inwardly of theirrespective outer edges. Conveyor belts 52 a and 52 b are driven by aconventional drive system (not shown) as would be understood by thoseskilled in the art. Heater assembly 50 includes a first or upper heatingcomponent 54 and a second or lower heating component 56 which arepositioned on opposed sides of panel assembly 10 and conveyor belts 52 aand 52 b. Heating component 54 is positioned above panel assembly 10 forheating surface 14, the adhesive-free side of panel 12 and is,preferably, adapted to heat a perimeter portion of surface 14 of panel12 which corresponds and is aligned with bead 26 or 26′. Heatingcomponent 56, on the other hand, is positioned below panel assembly 10and conveyor belts 52 a and 52 b and is adapted to heat side 16 and,more specifically, to heat bead 26 or 26′.

Heating component 54 provides heat energy to side or surface 14 of panelassembly 10 and preferably includes a shortwave infrared radiationsource such as a plurality of shortwave infrared emitting lamps 58 (FIG.2), for example the high density tubular quartz (T3) tungsten filamentlamps which are available from Research, Inc. of Minneapolis, Minn.Lamps 58 preferably emit peak radiation of less than about 2.5 microns.More preferably, lamps 58 emit a peak radiation in about the 0.6 to 2.5micron region of the infrared spectrum. More preferably, lamps 58 emitpeak radiation of less than about 1.0 micron. In the illustratedembodiment, lamps 58 are preferably supported in a housing 59 and arearranged in a generally parallel spaced apart relationship to the panelassembly 10. In addition, lamps 58 are preferably equally spaced toprovide a uniform application of heat to the perimeter portion ofsubstrate panel 12. Alternately, lamps 58 may be arranged in anon-uniform manner to accommodate the topology of the panel assembly,for example a curved panel assembly, including a curved panel assemblywith a compound curve. Furthermore, lamps 58 are preferably removablymounted in housing 59 and can be reconfigured and rearranged in housing59 to accommodate variations in the shape and size of the panelassemblies.

In contrast, second heating component 56, which provides heat energy tobead 26 or 26′, preferably comprises a longwave infrared heater andincludes a longwave infrared radiation source, such as a quartz emitter60 (FIG. 2). Quartz emitter 60 preferably emits a peak radiation greaterthan about 2.5 microns in the infrared spectrum. More preferably, secondheating component 56 emits a peak radiation in a range of about 2.5 to8.0 microns. Most preferably, second heating component 58 emits peakradiation in a range of about 2.5 to 6.0 microns. Quartz emitter 60includes one or more heating elements 62 which are embedded in a fusedquartz medium or substrate 64 and is commercially available from CassoSolar of Pomona, N.Y. Alternately, heating component 56 may apply hotair to panel 12 and bead 26 or 26′ to heat bead 26 or 26′. Preferably,the hot air is directed onto the bead, with the central portion of thepanel 16 and heat sensitive attachments avoiding degradation. In anotherform, heating component 56 may comprise a black body radiator that emitsinfrared radiation in response to the shortwave infrared radiationemitted by lamps 58. For example, heating component 56 may comprise afused quartz body which would emit longwave infrared radiation.

In the illustrated embodiment, heating component 56 preferably comprisesa perimeter heater, as shown in FIG. 1, having heat emitting portions orsections 66, 68, 70, and 72 which are aligned with adhesive bead 26 onpanel 12 and, preferably, includes a non-heat emitting central portionor opening 74 so that the heat which is emitted from second heatingcomponent 56 is substantially localized at the adhesive bead 26 ratherthan the entire panel assembly 10. Alternately, heating component 56 maybe provided with a heat directer, such as a heat shield which localizesthe heat on bead 26 and is adapted to shield or mask the central portion80 and molded gasket 20 to protect substrate panel 12 and molded member20 from degradation.

As described above, first heating component 54 is positioned above panelassembly 10 so that the heat emitted from lamps 58 is directed to theadhesive-free-side of panel 12. Furthermore, in order to localize theheat from lamps 58 onto the portion of surface 14 of panel 12 whichcorresponds to or is aligned with adhesive bead 26, heater assembly 10further preferably includes a heat localizer, for example a heat shield76. Heat localizer 76 is interposed between first heating component 54and panel assembly 10 and includes a perimeter opening 78 whichcorresponds to the perimeter portion of upper surface 14 correspondingto and aligning with bead 26. In this manner, the heat from lamps 58 islocalized on the glass side of bead 26, and the heat sensitivecomponents, such as molded member 20 which tend to degrade under hightemperatures such as those associated with activation of adhesive 26,are shielded from the shortwave infrared radiation emitted from lamps58. In addition, heat shield 76 shields or masks the central portion 80of panel 12 to avoid introduction of cracks and delamination.Furthermore, by shielding or masking the central portion of panel, panelassembly 10 is easier to handle.

Referring to FIG. 2, heat shield 76 includes a reflective surface 82 todirect the heat away from molding 20 and central portion 80 of panelassembly 10. For example, reflective surface element 82 may comprise apolished metal sheet backed with an insulating substrate 84, whichtogether minimize the amount of heat transmitted from first heatingcomponent 54 to molded member 20 and central portion 80 of panelassembly 10. In addition, heat shield 76 may include an air gap betweenreflective surface element 82 and plastic substrate 84 which increasesthe dissipation of heat and, therefore, improves the shielding of therespective heat sensitive components of panel assembly 10. Alternately,heat shield 76 may comprise a ceramic or a metal coated or reflectorclad ceramic. Furthermore, shield 76 may comprise a double pane shield,for example an aluminum double pane with preferably, a gaseous layer,such as of air or an inert gas, such as argon or nitrogen or the like,or an insulating material, such as fiberglass or xerogel or the like,between the panes serving as an insulator. Moreover, shield 76 may besubstantially opaque or may be only partially opaque so as to,optionally, provide restricted heating of the shielded window panelregion (so as to avoid thermal differences between the shielded regionand the perimeter unshielded region and, thus, alleviate thermalstresses). For example, shield 76 can comprise a panel (such as of aspecialized near infrared absorbing glass) that is only partiallytransmitting to shortwave infrared radiation (for example, is less than50% transmitting). Also, shield 76 can have a gradient in its thermaltransmission property with its outer edge regions being, preferably,substantially opaque and its more central regions being less opaque,i.e. more partially opaque. Thus, shield 76 can be a gradient heatshield that heats the central window panel regions least (distal fromthe panel edge region where the bead 26 is generally disposed) and thatheats the window panel more t the edge regions closer where the bead 26is disposed. Such a gradient heat shield can obviate thermal stressesbetween the shielded and unshielded regions of the window panel, whileproviding adequate heat shielding to protect any heat vulnerableattachments to the window panel, or protect any laminating materialsused. For example, shield 76 can comprise a near infrared radiationabsorbing glass panel that transmits less than about 10% of incidentshortwave infrared radiation at its center regions, but that transmitsgreater than about 70% incident shortwave infrared radiation at its edgeregions, thus acting as a gradient heat shield for the window panel.Furthermore, the outer perimeter portion 76 b of the shield may have ahigher shielding efficiency than central portion 76 a. In this manner,the thermal gradient across panel 10 may be balanced to control thethermal stresses in the panel due to the localized heating.

Preferably, shield 76 is supported by housing 59 of first heatingcomponent 54, for example by conventional fasteners and the like, withthe central portion 76 a being supported independently from theperimeter portion 76 b of shield 76 to assure that opening 78 remainsunobstructed.

Referring to FIG. 2C, a second embodiment of heating component 54′ andheat localizer 76′ are shown. Heating component 54′ comprises aperimeter shortwave heater and includes lamps 58′, which are arranged toform a perimeter heater such that lamps 58′ are generally aligned overthe portion of upper side 14 of panel assembly 10 which is aligned withbead 26. Heat localizer or directer 76′ includes an inner heat directingmember 78′ and an outer heat directing member 80′ which are aligned todirect the heat from lamps 58′ onto the localized or discrete peripheralportion of the upper side 14 of panel assembly 10 which is aligned withbead 26. Inner heat directing member 78′ is preferably supported onhousing 59′ inwardly of the innermost lamp 58 a′. Outer heat directingmember 80′, on the other hand, is supported on housing 59′ outwardly ofoutermost lamp 58 b′ so that substantially all the infrared radiationemitted from lamps 58′ is directed between inner and outer heatdirecting members. Preferably, outer heat directing member 80′ is cantedor slanted inwardly so that the heat from lamps 58′ is localized orfocused on that portion of the upper side 14 of panel assembly 10.Optionally, heat localizer or directer 76′ may include intermediate heatdirecters (not shown) which extend from housing 59′ between inner andouter heat directers 78′ and 80′. In this manner, increased control overthe applied heat may be obtained when lamps 58′ are individuallycontrolled. Furthermore, heat directer members 78′ and 80′ may compriseannular members or, optionally, may each comprise a plurality ofoverlapping segmented members, whose position or orientation can beadjusted by varying the degree of overlap between each of the individualsegmented members.

It can be appreciated from the foregoing that the shortwave infraredradiation emitted from lamps 58 heats a localized or a discrete portionof substrate panel 12, which in effect becomes a heat source for bead26, and heats bead 26 through interface surface 30 between panel 16 andbead 26. On the other hand, the longwave infrared radiation emitted fromheater assembly 56 directly heats bead 26 and, more specifically, heatsouter skin surfaces 32, 34 and outer extremity portion 31 of adhesivebead 26. Together, shortwave heating component 54 and longwave heatingcomponent 56 uniformly heat adhesive bead 26 so that its central coreportion 36 achieves the desired temperature without over heating theskin or outer surface portion and, more significantly, its outermostextremity portion. It should be understood from the foregoing that thegeometry of bead 26 may result in bead 26 having at least threetemperatures, for example, a bead core temperature, a bead skin surfacetemperature, and a bead interface temperature. Depending on the balanceof the shortwave and longwave infrared radiation, these threetemperatures may vary considerably. Desirably, in order to activate theadhesive properties of bead 26, the core portion 36 is heatedsufficiently to at least its minimum activation temperature while theinterface and outer skin surface temperatures are preferably maintainedbelow the adhesive degradation temperature.

Preferably, adhesive bead 26 comprises a heat activated adhesive whichhas a minimum activation temperature of at least about 50° C. to 60° C.to provide a safety margin against unintentional activation, such asduring shipment from a remote ready-to-install window facility to avehicle assembly plant. More preferably, adhesive bead 26 has a minimumactivation temperature of at least about 80° C., and even morepreferably has a minimum heat activation temperature of less than about120° C. Most preferably, adhesive bead 26 has a minimum heat activationtemperature in a range of about 80° C. to 110° C. For example, however,where the window panel is such as a laminated windshield or side windowor backlite comprising two glass sheets laminated with a polymer innerlayer, such as plasticized polyvinyl butyryl, or silicone or the like,it is preferable that the activation temperature of the adhesive be lessthan or equal to about 150° C., more preferably less than or equal toabout 125° C., and most preferably less than or equal to about 105° C.Also, when a ready-to-install adhesive is applied on or adjacent to agasket such as a polyvinyl chloride (PVC) molding, a urethane molding,an elastomeric molding or the like, it is preferable that the heatactivation temperature of the adhesive be about less than or equal to125° C., more preferably less than or equal to about 115° C., and mostpreferably less than or equal to about 105° C. In addition, the adhesivebead 26 preferably has a maximum activation temperature less than about160° C., more preferably, less than about 130° C., and most preferablyless than about 120° C. When activated, the core temperature of adhesivebead 25 is, preferably, in a range of about 50° C. to 160° C., morepreferably in a range of about 70° C. to 120° C., and most preferably ina range of about 80° C. to 110° C. In order to control and, morepreferably, eliminate degradation of the bead material, the shortwaveand longwave infrared heaters are controlled and/or balanced so that thebead skin surface temperature at the bead's skin or outer surfaceportion or region and/or at least a portion of the bead's skin or outersurface portion, does not exceed the temperature of the central coreportion of the bead more than about 40° C., more preferably, more thanabout 20° C., and most preferably more than about 10° C. For example,the bead surface temperature is preferably maintained less than about170° C., more preferably less than about 140° C., and most preferablyless than about 120° C. While no maximum dwell times are required, inorder to provide a process suitable for coordination with productionline assembly, heater 50 preferably heats bead 26 to its activationtemperature in less than about ten minutes, more preferably, in lessthan about five minutes, and most preferably, in less than about twominutes. In some applications, heater 50 may heat bead 26 to itsactivation temperature in a range of about 5 seconds to about 20seconds, provided that the core of bead 26 reaches its desiredactivation temperature and is uniformly heated.

A preferred heat activated adhesive preferably comprises an adhesiveforming resin such as urethane resin, polyether resin, acrylic resin,oxyalkylene resin, vinyl resin, or a similar adhesive forming resin. Theadhesive may include latent accelerants and/or catalysts (such as organometallic catalysts such as tin catalysts) and the like that are heatactivated at line-side and/or are formed when exposed to heat above asuitable threshold temperature, including for example monomeric oroligomeric or partially polymerized precursors of window fixingadhesives, such as of urethane, polyether, oxyalkylene, acrylic, vinyladhesives and the like. Such latent accelerants and/or catalysts can bemicroencapsulated or can be formed through the heat activation of theadhesive composition. Once so activated, the window fixing adhesive issuitable for securing panel assembly 10 to the vehicle. More preferably,the ready-to-install adhesive is an activatable resin composition, forexample, an oxyalkylene polymer having in its structure at least onesilicon-containing group which bears a hydroxyl or hydrolyzable groupbonded to the silicon atom and which can cross-link through thecondensation of silanol. Preferably, the resin further includes carbonblack and an oxyalkylene polymer free from any cross-linking group aswell as latent accelerants and/or catalysts, stabilizers and the like.In such manner, the ready-to-install heat activated adhesive ispreferably not activated until panel assembly 10 is line-side, and isdispensed onto the panel at the remote RTI window plant, and shipped tothe vehicle assembly plant, in an uncured or only partially cured and/orin an unformed or only partially formed state.

As shown in FIG. 3A, in order to accommodate the conveyor speed,multiple heating stages having first, second, third, and fourth stageheaters 50′, 50″, 50′″, and 50″″ arranged in series can be used in whichadhesive bead 26 is heated, for example in thirty to sixty second stagesuntil the final temperature has been reached. Heaters 50′-50″″ arepreferably of similar construction to heater assembly 50 and, therefore,reference is made to that assembly for further details of each heater50′, 50″, 50′″ or 50″″. The heating times and durations vary dependingon the type of substrate panel whether glass and/or whether tempered orlaminated, due to the differences in thermal conduction. Alternatively,as best seen in FIG. 3B, first, second, third, and fourth heaters 50′,50″, 50′″, and 50″″ may be positioned adjacent conveyor 52. In thisarrangement, panel assemblies 10 are delivered to heaters 50′, 50″,50′″, and 50″″ and, after heating, are moved from heaters 50′, 50″,50′″, and 50″″ for placement on conveyor 52. In this arrangement, panelassemblies 10 are inserted in the respective heaters 50′, 50″, 50′″, and50″″ at different and successive times so as to allow sufficient dwelltimes for each assembly so that heated assemblies are available whenneeded as successive vehicles pass along the assembly line. Thus, incontrast to the heaters arranged in series over conveyor 52, stageheaters 50′, 50″, 50′″, and 50″″ preferably operate out of phase so thatwhen a panel assembly 10 is heated to its activation temperature, thepanel assembly may be removed from the respective heater and immediatelyplaced on conveyor 52 without delay for subsequent installation into avehicle. For example, where conveyor indexes every 60 seconds, stageheaters 50′, 50″, 50′″, and 50″″ would preferably operate out of phaseby 60 seconds.

Referring to FIGS. 4-6, a preferred embodiment 150 of the heaterassembly is shown. Heater assembly 150 includes a first or upper heatingcomponent 154 and a second or lower heating component 156, which arerespectively positioned above and below panel assembly 10′, which issupported on a conveyor 152, and are adapted to move from a holding ornon-heating position to a heating position, as will be more fullydescribed below. Conveyor 152 is a conventional conveyor and includes aconveyor belt 152 a which is driven by a conventional drive system. Thedrive system includes a gear box and motor 152 b which is coupled tobelt drive sprockets 152 c by a drive chain 152 d, all of which aresupported by a conveyor frame 152 e. Panel 10′ is supported on conveyor152 by a pair of locator members 153 which support panel 10′ above andspaced from conveyor belt 152 a with holders 153 a which support panelassembly 10′ inwardly of its outer periphery 18′. Locator members 153are secured to conveyor belt 152 a and are grouped in pairs which aresufficiently spaced apart along belt 152 a so that only one panel at atime is positioned in heater 150. Panel assembly 10′ may be of similarconstruction to panel assembly 10 and, therefore, for further details ofpanel assembly 10′, reference is made to panel assembly 10.

Heating component 154 and heating component 156 are supported by a frame159, which straddles conveyor belt 152 a and panel assemblies 10. Frame159 includes spaced apart column members 160 which are interconnected byupper and lower transverse members 162 a and 162 b and upper and lowerlateral members 164 a and 164 b. It should be understood that framemembers 160, 162 a, 162 b, 164 a, and 164 b may comprise conventionalstructural members, for example tube steel, angle members, or channelmembers. Frame 159 further includes movable upper support members 166 aand 166 b and movable lower support members 168 a and 168 b whichrespectively support heating component 154 and heating component 156 onframe 159. Each upper support member 166 a and 166 b preferably includesan elongate member 170 a having a pair of threaded collars 172 a and 172b at ends 171 a and 171 b, which are supported on and engage threadedshafts 176 a, 176 b, 176 c, and 176 d which are supported on frame 159.Each lower support member 168 a, 168 b similarly includes an elongatemember 170 b having threaded collars 174 a and 174 b at respective ends173 a, and 173 b, which are supported on and engage threaded shafts 176a, 176 b, 176 c, and 176 d. Shafts 176 a, 176 b, 176 c, and 176 d aresupported by and extend between respective upper mounting brackets 178a, 178 b, 178 c, and 178 d and lower mounting brackets 179 a, 179 b, 179c, and 179 d, which in turn are respectively supported on upper andlower transverse members 162 a and 162 b. Threaded shafts 176 a, 176 b,176 c, and 176 d are driven by a gear box and motor assembly 180, whichis supported by frame 159 and coupled to respective sprocket gears 182a, 182 b, 182 c, and 182 d, which are mounted to the upper ends ofthreaded shafts 176 a, 176 b, 176 c, and 176 d, by drive chains 184.

Each shaft 176 a, 176 b, 176 c, and 176 d preferably includes a first orupper portion and a second or lower portion which are threaded inopposite directions, so that when shafts 176 a, 176 b, 176 c, and 176 dare rotated and driven by gear box and motor assembly 180, upper supportmembers 166 a and 166 b will move generally simultaneously in anopposite direction from lower supports 168 a and 168 b to move heatingcomponents 154 and 156 either toward panel assembly 10 to theirrespective heating positions or away from panel assembly 10 to theirrespective holding positions. Alternately, upper collar members 172 aand 172 b may be threaded in opposite directions from lower collarmembers 174 a and 174 b to achieve the same result.

Similar to the first embodiment, heating component 154 preferablyincludes a shortwave infrared radiation source, for example a pluralityof shortwave infrared emitting lamps 158. Reference is made to lamps 58of heating component 54 described in reference to heater 50 for furtherdetails of lamps 158. Lamps 158 are supported in a housing 185, whichincludes mounting flanges 186 for coupling heater housing 185 to uppermovable supports 166 a and 166 b (FIG. 5) so that heating component 154can be moved up and down shafts 176 a, 176 b, 176 c, and 176 d. Flanges186 are preferably releasably secured to supports 166 a and 166 b byconventional fasteners, such as bolts or clamps so that heatingcomponent 154 may be removed for service or substitution.

Heating component 156 preferably includes a source of longwave infraredradiation, such as a quartz emitter similar to heater 56 of the firstembodiment, which is supported in a housing 188. Similar to housing 185,housing 188 includes mounting flanges 190, which are coupled to movablesupports 168 a and 168 b, for example by releasable fasteners, to permitrepositioning of heater 156 from its holding position to its heatingposition. Since quartz emitters have a relatively long heat-up time, itis preferred to leave the longwave infrared radiators energized duringthe assembly process. In order to control the application of heat,therefore, heating components 154 and 156 are moved in relatively closeproximity to panel assembly to heat panel assembly 10′ and moved awayfrom panel assembly 10′ to essentially discontinue application of heat.In addition, the proximities of heating components 154 and 156 to panel10′ may be adjusted to control the heating process should the variationsin the panel assembly affect the rate of heating. It should beunderstood, however, that lamps 158 (and lamps 58) have essentially noheat-up time and, therefore, lamps 158 (and 58) may be de-energized forconservation of energy. Optionally, heating component 154 may besupported in a fixed position. But, in order to accommodate varyingdimensions between panel assemblies 10′ it is preferred to provide frame159 with upper and lower movable supports to permit repositioning ofboth heating components 154, 156 and which would additionally permit thepositions of heating components 154 and 156 to be reversed if desired.

As best seen in FIG. 5, heater 150 also includes a heat localizer 195which is interposed between first heating component 154 and panelassembly 10′. Heat localizer 195 is substantially similar to heatlocalizer 76 as described above. Alternatively, heat localizer 195 maybe similar to heat localizer 76′. In this manner, the infrared radiationfrom lamps 158 is localized on the glass side of the adhesive oradhesive-free side of panel assembly 10 and is directed away from heatsensitive components, as described in reference to the first embodiment.In a similar manner to heat localizer 76, heat localizer 195 may besupported by heating component 154 or optionally supported by frame 159.

Referring to FIGS. 7-9 a third preferred embodiment 250 of a heaterassembly of the present invention is illustrated. Heater assembly 250includes a first or lower heater component 254 and a second or upperheater component 256, which are respectively positioned below and abovea panel assembly 210 and supported on frame 259. Frame 259 includesupper and lower frame members 259 a and 259 b which respectively supportupper and lower heater components 256 and 254. Heater components 254,256 are preferably adapted to move from a holding or non-heatingposition to a heating position in a similar manner to the previousembodiments; therefore, reference is made to the previous embodimentsfor further details of frame 259. Panel assembly 210 is preferablysupported on conveyor 252 in a similar manner to the previousembodiments. Therefore, reference is made to conveyor 152 for thegeneral details of the conveyor and how the conveyor supports panel 210.

Referring to FIG. 8, panel assembly 210 includes a substrate or panel212, preferably a glass panel, an optional molded member 220, such as agasket, and a bead 226 of heat activated adhesive. Substrate 212includes first and second opposed sides 214 and 216 which respectivelydefine adhesive sides and non-adhesive sides 210 a and 210 b of panelassembly 210. Bead 226 is formed, by for example extrusion, on adhesiveside 210 a of panel assembly 210 and preferably on a peripheral portion212 a of substrate 212 adjacent molded member 220. It should beunderstood that panel assembly 210 may not include a molded member. Inthe illustrated embodiment, however, panel assembly 210 includes moldedmember 220 which comprises a three-sided gasket. It should also beunderstood by those skilled in the art that molded member 220 maycomprise other molded members, including for example a single-sided sealor gasket, a two-sided gasket, or the like. Bead 226 includes aninterface surface or portion 230, a core portion 236, and outer skinsurfaces 232 and 234 in a similar manner to bead 26 of the previousembodiments. Interface portion 230 directly contacts adhesive side 210 aof panel assembly 210 and provides a surface through which heat istransmitted to bead 226 from substrate 212 as will be more fullydescribed below. In addition, outer skin surfaces 232 and 234 convergeto form a tip and provide a surface through which heat is transmitted tocore portion 236, as will be more fully described below.

Heater component 254 is supported by lower frame member 259 b andpreferably includes one or more shortwave infrared radiation sources,for example one or more shortwave infrared emitting lamps 258. Referringto FIG. 12, heating component 254 preferably comprises a plurality ofrelatively short elongate shortwave infrared emitting lamps 258 whichare arranged with overlapping ends so that they can be adjusted toaccommodate varying sizes of panel assemblies. In addition, by providinga plurality of overlapping lamps, lamps 258 can be arranged in acircular pattern and/or to follow the contours of the glass panelassembly. As best seen in FIG. 12, each emitting lamp 258 includes aheat emitting zone 258 a and a non-heat emitting zone 258 b. Preferablylamps 258 are arranged to provide a uniform heat profile to panel byoverlapping non-heat emitting zones 258 b and aligning heat emittingzones 258 a to provide a generally continuous and linear source of heatfrom lamps 258.

Heating component 256 also supported on frame 259 by upper frame member259 a, on the other hand, preferably includes a longwave infraredradiation source. As shown in the illustrated embodiment in FIGS. 8 and9, heating component 256 may comprise a plurality of quartz emitters 260which are embedded in a fused quartz medium substrate 264 in a similarmanner to heating component 56. Furthermore, heating component 256preferably heats with a thermal mass temperature in a range of about450° F. to 900° F. More preferably, second heating component 256produces or heats with a thermal mass temperature in a range of about500° F. to 750° F. Most preferably, second heating component 256produces or heats with a thermal mass temperature in a range of about650° F. to 700° F. In addition, as described in reference to theprevious embodiments, second heater component 256 preferably comprises aperimeter heater which directs heat to perimeter 212 a of substrate 212and, more specifically, directs heat directly onto the adhesive bead 226which is on adhesive side 210 a.

Referring again to FIG. 8, first heating component 254 optionallyincludes a heat directer or localizer 276 which directs the heat fromlamps 258 onto a portion of substrate 212 which is generally alignedwith bead 226. Further, heat localizer 276 shields the central portionof the panel assembly 210 and molded member 220 from the heat which isemitted from heating component 254. In this embodiment, as shown in FIG.11, heat localizer 276 comprises a shield which is preferably formedfrom a plurality of slidably interconnected shield members 276 a, 276 b,and 276 c which define a perimeter or heater opening 278 between members276 a and 276 c. Heater opening 278 generally corresponds to perimeterportion 212 a of substrate 212 adjacent molded member 220 andcorresponds to and generally aligns with adhesive bead 226. It should beunderstood that when adhesive bead 226 does not follow the perimeter ofsubstrate 212, however, heater opening 278 will not follow the perimeterof the substrate and, instead, will follow bead 226. As best seen inFIG. 11, each shield member 276 a, 276 b, and 276 c includes an elongateopening 279 a, 279 b, or 279 c, respectively, which receives anadjustable fastener and washer assembly 280. Fastener and washerassemblies 280 permit adjustment of the respective shield members 276 a,276 b, and 276 c. In the illustrated embodiment, each releasablefastener and washer assembly 280 comprises a threaded fastener 281 and apair of enlarged washers 282 which are positioned on opposed sides ofthe respective overlapping shield members to provide bearing surfacesfor fastener 281 and, further, to frictionally hold the respectiveshield members 276 a, 276 b, and 276 c in position when fasteners 280are tightened. As will be understood by those skilled in the art, whenfasteners 281 are loosened, shield members 276 a, 276 b, and 276 c maybe adjusted to permit lengthening and shortening of one side of shield276 and rotation of shield member 276 a about the interconnectionbetween shield member 276 a and shield member 276 b. In this manner,shield 276 can be adjusted to suit the configuration of panel assembly210 and bead 226 as needed in order to direct heat onto that portion ofsubstrate 212 which will effectively heat bead 226 and to shield thecentral portion of substrate 212 and molded member 220 from excessiveheat.

Referring to FIG. 9, lamp or lamps 258 of heating component 254 arepreferably aligned with central axis 226 a. However, each lamp 58 may beoffset from the central axis 226 a of adhesive bead 226 by a distance A.Distance A is preferably less than 24 inches, more preferably less than12 inches, and most preferably one inch or less. Furthermore, preferablylamp 258 is preferably spaced at a distance B of less than 24 inchesfrom non-adhesive side 210 b of panel assembly 210, more preferably,less than 12 inches from non-adhesive side 210 b, and most preferably,less than 3 inches away from the non-adhesive side of panel assembly210.

In the illustrated embodiment, heater component 256 also optionallyincludes a heat directer or heat localizer 277 which includes reflectivewalls 277 a and 277 b which direct or localize the heat emitted fromheating component 256 on outer skin surfaces 232 and 234 of bead 226. Asbest seen in FIG. 8, reflective sides 277 a and 277 b may be extendedclosely adjacent to adhesive side 210 a of panel assembly 210 and,further, preferably straddle adhesive bead 226. In this manner, moldedmember 220 and the central portion of substrate 212 are shielded ormasked from the heat which is emitted from second heating component 256.

In a similar manner to first heater component 254, second heatercomponent 256 is spaced at a distance C from adhesive side 210 a ofpanel assembly, with distance C being preferably less than 24 inches,more preferably less than 12 inches, and most preferably less than 3inches from adhesive side 210 a. In addition, second heater component256 is preferably aligned with central axis 226 a of bead 223 but may beoffset preferably less than 24 inches, more preferably less than 12inches, and most preferably less than 1 inch from central axis 226 a.

Heat localizer 277 also includes a perimeter opening 279 defined betweenreflective sides 277 a and 277 b for directing heat from heatercomponent 256 onto outer skin surfaces 232 and 234 of bead 226. In thismanner, the heat from heating component 256 is localized on bead 226 andthe heat sensitive components, such as molded member 220, which tend todegrade under high temperatures such as those associated with activationof adhesive bead 226, are shielded from the radiation emitted fromheating component 256. Furthermore, heat localizer 277 shields or masksthe remaining portion of panel assembly 210 to avoid introduction ofcracks and delamination. As noted in reference to the earlierembodiments, by shielding or masking the central portion of the panel,panel assembly 210 is easier to handle.

Optionally, heat localizer sides 277 a and 277 b include reflectivesurfaces 280 a and 280 b, respectively. For example, sides 277 a and 277b may comprise polished sheet metal members backed with an insulatingsubstrate as described in reference to the earlier embodiment of heatshield 76. For further details of heat shield 277, reference is made toheat shield 76.

Referring to FIG. 10, another embodiment 310 of a glass panel assemblyis shown. In this embodiment, panel assembly 310 includes a glass panelsubstrate 312 with a three-sided gasket 320 formed on its peripheralportion 312 a and an adhesive bead 326 formed on gasket 320. Bead 326 isapplied to a portion 320 a of gasket 320 such that its interface surfaceor portion 330 contacts gasket 320. Similar to the previous embodiment,panel 310 is heated by first heater component 254 and second heatingcomponent 256. In this application, however, heater component 254 ispreferably aligned and positioned over a portion of panel 312 adjacentgasket 320 but offset from bead 326. Similarly, heater component 254preferably includes heat localizer or heat shield 276 which directs heataway from gasket 320 and instead localizes the heat on the portion ofsubstrate 312 adjacent gasket 320 and offset from bead 326. In thisapplication, glass panel 312 transmits heat to gasket 320 whichtransmits heat to adhesive bead 326 through interface surface 330.Consequently, both panel 312 and molded member 320 act as black bodyradiators for heating adhesive 326. On the other hand, heater component256 is preferably aligned over adhesive bead 326 to direct heat on outerskin surfaces 332 and 334 of adhesive bead 326 in a similar manner tothe previous embodiments. Again, lamps 258 are preferably spaced lessthan 24 inches from the non-adhesive side 310 b of panel assembly 310,more preferably, less than 12 inches from non-adhesive side 310 b, andmost preferably, less than 3 inches from non-adhesive side 310 b. Heatercomponent 256 is preferably spaced from substrate 312 less than 24inches from the adhesive side 310 a of panel assembly 310, morepreferably, less than 12 inches from adhesive side 310 a, and mostpreferably, less than 3 inches from adhesive side 310 a. Mostpreferably, heater component 256 is spaced approximately two inches fromadhesive side 310 a.

In the preferred form of the invention, heating assembly 250 includes acooling apparatus 290 to cool substrate 212 or 312 after the panelassembly 210 has been removed from heating assembly 250 so that panelassembly 210 or 310 can be handled manually without injuring the worker.Cooling apparatus 290 may be supported by frame 259 or may be locatedadjacent the conveyor downstream from heater assembly 250. Preferably,when handling glass panel assembly 210 or 310, the substrate should besufficiently cooled to permit manual handling by workers. At the sametime, the cooling of the substrate must be balanced with the heating ofthe bead and substrate such that the cooling does not hamper the core ofthe bead reaching its activation temperature. Preferably, panel assembly210 or 310 is cooled such that the region non-adjacent the bead iscooled while leaving the bead region at its elevated temperature.Without active cooling, it has been found that the temperature in onepanel assembly sample having substrate dimensions of 60″×24″ and beaddimensions of 8 mm×14 mm does not drop below 120° F. until approximatelynine minutes after the heating stage is complete and eight and a halfminutes after the core reaches the heat activation temperature.Preferably, the handling portion of the substrate 212 or 312 is cooledto a temperature below a preferential temperature as quickly as possibleand, preferably, within fifteen minutes, more preferably, within nineminutes, and most preferably less than two minutes after the lastheating stage is complete or the bead has reached its heat activationtemperature.

Referring to FIG. 7, cooling apparatus 290 directs a gaseous stream, forexample air or an inert gas, such as argon or nitrogen or the like, ontoa portion of the glass panel in order to cool substrate 212 or 312 tothe desired temperature within the desired time frame. Preferably,cooling apparatus 290 directs the gaseous stream on to the peripheralportion of the glass panel. Cooling apparatus 290 preferably comprises ablower, such as a turbo fan or an air knife blower, for example an airknife blower commercially available from EXAIR® Corporation ofCincinnati, Ohio. In addition, the blower preferably directs the gaseousstream onto the peripheral portion of the substrate at an angle in arange of about 0° to 85° from central axis 226 a of bead 226 and, morepreferably, in range of about 40° to 60° from the central axis 226 a,and most preferably at an angle of about 45° from central axis 226 a. Inorder to assure that bead 226 (or 326) achieves its activationtemperature, however, the cooling must be matched or balanced with theheat from heater components 254 and 256.

Cooling apparatus 290 preferably applies a sufficient gaseous stream tocool the peripheral portion of substrate 212 or 312 so that panelassembly can be handled while in a manner not to interfere with theheating of bead. Referring to the example illustrated in FIG. 13, aftercompleting the last heating state and the glass is held at ambienttemperature at 400, the glass temperature gradually degrades from itspeak temperature at 401 as shown on curve 402. The temperature of theglass temperature does not reach 120° F. at 403 until approximately nineand a half minutes after the heating stage is complete. In contrast,when the glass substrate is subjected to cooling by a fan, for example aturbo fan, the glass temperature drops from its peak temperature at 401at a faster rate as shown on curve 404 to reach 120° at 405 withinapproximately two minutes. If the substrate is cooled by an air knifeblower, the glass substrate degrades from its peak temperature at 401 atan even faster rate as shown on curve 406 and will reach 120° at 408within approximately one and a half minutes. The preferred maximumtemperature or preferential temperature for the substrate is 250° F.,with a more preferred maximum temperature of 175° F., and a mostpreferred maximum temperature of 120° F. In order to decrease theprocessing time, it is desirable to reduce the temperature of thehandling portion of the glass substrate to below the desired maximumwithin 15 minutes or less, more preferably within 9 minutes or less, andmost preferably within 2 minutes or less.

Referring to FIG. 14, the temperature profile of the respective portionsof the bead, specifically the tip (as defined between the outer skinsurfaces), the core portion, and the interface portion or base of onesample assembly panel, are illustrated by curves 502, 504, and 506,respectively. The heat is applied at 500 with the interface portionreaching its maximum temperature at 508 of approximately 135° C. withinapproximately one and a half minutes of initiating the heating. Incontrast, the temperature of the tip portion of the bead reaches amaximum temperature of approximately 95° C. at about the same time asthe interface portion reaches its maximum. The core portion, however,exhibits a slower temperature increase and reaches a preferredactivation temperature of 80° C. at approximately two minutes. It can beseen from FIG. 14, that even after the heat is removed at 508, the coreportion of the bead increases its temperature to a peak temperature ofapproximately 85° C. from which it degrades slowly as compared to theglass as shown on curve 504 of FIG. 14. In effect, the glass substrateacts as a heat sink and stores heat for a discrete period of time tocontinue heating the bead. Further, the geometry and composition ofsubstrate 212 may affect the heating process. In some applicationscooling may commence right after the heating stage is complete. In otherapplications, cooling may be initiated right after the bead has reachedits heat activation temperature. In yet others, cooling may be initiatedeven during the heating process and even before the bead has reached itsactivation temperature. For example, when the cooling apparatus issupported by the heating apparatus, the cooling process may initiatedduring or after the heating process. Further, since heating components254 and 256 may be energized simultaneously or individually energizedand de-energized for selected periods of time, it should be understoodthat other sequences may be realized.

Referring to the cooling profile of FIG. 15, the cooling profileincludes the initial heat profiles of the outer skin surface or tip,core portion, and the interface portion as represented by the initialportions of curves 502′, 504, and 506′. In addition, the cooling profileincludes the temperature profile of the glass as shown by curve 510′,which profile starts after the heating stage has been completed at 508′.The cooling profile reflects the temperature of the respective portionsof the bead and the glass with cooling being initiated at approximatelytwo and a half minutes after the initial heating process at 500′ andapproximately one minute after the heat is removed at 508′. As shown inFIG. 15, the temperature of the glass rapidly decreases to below 48° C.or 120° F. within about two minutes after the initiation of the coolingstep. It should be further noted that despite the initiation of thecooling at 512′, the temperature of the core continues to rise and peaksat 514′ at approximately 88° C. which occurs approximately 30 secondsafter the cooling is initiated at 512′. It should be understood thatgraphs shown in FIGS. 13-15 are for illustrated purposes only andprovide one example of balancing of the heating and cooling to achieveactivation of the adhesive and yet cool the substrate sufficiently topermit manual handling of the panel assembly.

In order to achieve the balance between the activation of the adhesivebead and the cooling of the glass panel for handling, the shortwave andlongwave infrared radiation is preferably applied for at least 5 secondsbut for less than about 10 minutes and the application of the coolingair is applied for at least 30 seconds within 5 minutes before of afterthe termination of the heating step or the bead reaches its activationtemperature. Preferably, the substrate is cooled to its preferentialtemperature within 15 minutes or less, more preferably within 9 minutesor less, and most preferably within 2 minutes or less of the terminationof the heating stage or the bead reaching its heat activationtemperature. It should be understood that in order to accommodate theflow of the assembly line conveyor, shortwave and longwave infraredradiation heating and the cooling step may also be applied in stages ina similar manner to that described in the previous embodiment.

Referring to FIG. 10A, a third embodiment of panel assembly 210 isillustrated. Panel assembly 210′ includes a substrate 212′, preferably aglass substrate, and an optional molded member, such as a gasket, and anadhesive 226′. In the illustrated embodiment, adhesive 226′ comprises apair of adhesive beads 226 a′ and 226 b′, each with a central axis 226c′ and 226 d′, respectively. Beads 226 a′ and 226 b′ are appliedadjacent molded member 220′ and are similarly extruded or otherwiseapplied to an adhesive side 210 a′ of panel 210′. To heat beads 226 a′and 226 b′, heater assembly 250′ includes a first heater component 256′and a second heater components 254′ which are respectively positionedover beads 226 a′ and 226 b′ on adhesive side 210 a′ and over a portionof substrate 212′ aligned with the beads on non-adhesive side 210 b′.Heater components 256′ generates longwave infrared radiation andpreferably includes quartz emitters 260′ which are embedded in a fusedquartz medium substrate 264′, similar to heater component 256. Heatercomponent 254′ preferably generates shortwave infrared radiation andincludes one or more lamps 258′. In general heater components 254′ and256′ are of similar construction to heater components 256 and 254,respectively, and therefore reference is made thereto for furtherdetails.

In this embodiment, beads 226 a′ and 226 b′ are generally smaller and,therefore, reach their respective heat activation temperatures morequickly than described in reference to the previous embodiments.Consequently, the processing time is reduced. Further, as the beadsrequire less heat or less heat input, cooling may be obviated since theglass temperature may be substantially lower than in the previousembodiments and may cool rapidly in ambient air to reach thepreferential temperature quite soon after completing the heating stageof the process.

As best seen in FIG. 10A , heater component 256′ is generally alignedover beads 226 a′ and 226 b′ such that heater components 256′ preferablydelivers the same heat profile to both beads. Similarly, heatercomponent 254′ is preferably aligned with beads 226 a′ and 226 b′ inorder to provide uniform heating to both beads. However, it should beunderstood, that heater component 254′ may optionally include arespective lamp 258′ associated with each bead, in which case, the lampswould preferably be aligned with the central axes 226 c′ and 226 d′ ofthe respective beads 226 a′ and 226 b′. However, as described inreference to the previous embodiments, the heater components may beoffset from the respective central axes of beads 226 a′ and 226 b′provided that the heater components' reflectors 277 a′ and 277 b′ and276′ compensate and reflect the heat from the respective heatercomponents to provide uniform heating of beads 226 a′ and 226 b′.

Panel assemblies 10, 10′, 210, and 310 described above are manufacturedaccording to a method which results in “ready-to-install” panelassembly. Heat activated adhesive bead 26, 226, or 326 can be applied tothe panel substrate 12, 212, or 312 at a location remote from theproduction site, such as a “just-in -time” plant. This preassemblyprocess eliminates a complicated step in the vehicle assembly line andremoves the expense and problems of handling and precautionary measuresthat can be associated with the chemicals forming the adhesive and theadhesive primers. Panel assemblies 10, 10′, 210, and 310 are preferablyheated using shortwave and longwave infrared radiation to activate theadhesive properties of heat activated adhesive bead 26, 226, or 326.Furthermore, the adhesive properties of the bead are activated quickly.Alternatively, panel assemblies 10, 10′, 210 and 310 may be heated byshortwave infrared radiation, with the shortwave infrared radiationdirected onto the non-adhesive side of the panel assembly and with ablack body radiator positioned on the adhesive bearing side of the panelassembly, as described earlier, which absorbs the shortwave infraredradiation and emits infrared radiation back toward the bead 26, 226, or326. Optionally, the panel assembly may be heated on both sides withshortwave infrared radiation or longwave infrared radiation. Moreover,the adhesive free side of the panel assembly may be heated with longwaveinfrared radiation, while the adhesive bearing side may be heated withthe shortwave infrared radiation.

Once assembled, panel assemblies 10, 10′, 210, and 310 are delivered tothe production site and placed on conveyor 52, 152, or 252 which thentransports the panel assembly to heater 50, 150, 50′, 50″, 50′″, 50″″,or 250 where heat is applied to the panel assembly (10, 10′, 210, or310). Heat, preferably in the form of shortwave infrared radiation, isapplied to the adhesive free side of the panel substrate (12, 212, or312) and, preferably, localized onto that portion of the adhesive freeside of panel 12, through for example a shield 76 or heat directer 76′,276, or 376 which is aligned with bead 26, 226, or 326 so that the panelsubstrate is heated in a localized area which corresponds to bead 26,226, or 326, by for example heat localizer 277. Bead 26 or 226 in effectdraws heat from the localized heated area of panel substrate 12 throughits glass interface surface or base 30. On the other hand, bead 326draws heat from localized area of the heated panel 312 through gasket320. Furthermore, heat, preferably in the form of longwave infraredradiation, is applied directly onto the bead side of panel assembly 10to directly heat bead 26, 226, or 326 through its skin surfaces.Preferably, the longwave infrared radiation is similarly directed to orlocalized on the bead, for example by way of a shield or by arrangingthe longwave infrared radiation source in a perimeter heater arrangementwhere the individual longwave infrared radiation sources are alignedwith the bead, as described in reference to heating assembly 250. As aresult, bead 26, 226, or 326 is heated from two sides-its base orinterface region (30, 230, or 330) and its outer skin surface region(32, 34; 232, 234; or 332, 334). By indirectly applying the shortwaveinfrared radiation, which provides high energy heating, and directlyapplying the longwave infrared radiation to the bead, adhesive bead 26,226, or 326 is heated in a controlled fashion which achieves uniformheating of the bead and yet avoids degradation of the adhesive itselfand further avoids degradation of the substrate panel and itssurrounding attachments, including molded gaskets such as 20, 220, and320. Uniform heating of the adhesive bead assures appropriate retentionof panel assembly 10, 10′, 210, or 310 in the vehicle.

As described previously, in order to uniformly heat the adhesive, thebead is preferably heated to an activation temperature in a range ofabout 50° C. to 160° C., more preferably, in a range of about 70° C. to120° C., and, most preferably, in a range of about 80° C. to 110° C. Byproviding an adhesive with a minimum or suitable activation temperature,unintentional activations can be avoided. In addition, in order toreduce or eliminate surface degradation of adhesive bead 26 or 226and/or of moldings, attachments, and structures that are attached to thepanel and/or are used in forming the panel, the shortwave and longwaveinfrared radiation are balanced by a control system to maintain thetemperature of the skin surface of bead 26, 226, or 326 to be preferablyless than about 170° C., more preferably less than about 140° C. and,most preferably, less than about 120° C. The balance of the shortwaveand longwave radiation is achieved through sensors 198 (FIG. 5), whichmay mounted to heater 50, 150, 50′, 50″, 50′″, 50″″, or 250 to monitorthe surface temperature of the adhesive bead. Sensors 198 are coupled tocontrol assembly 200 (FIG. 5), which may provide a manual operation modeand/or may be preprogrammed to maintain the temperature of the adhesivebead to a desired temperature. Control assembly 200 is electricallycoupled to gear box and motor assembly 180, which sends actuationsignals to motor assembly 180 to control the position of heatingcomponents 154 or 254 and 156 or 256. Optionally, control assembly 200may be further coupled to the individual infrared radiation sources inheating components 154 or 254 and 156 or 256 to provide an override inthe event motor assembly 180 malfunctions or to provide adjustment ofthe levels of power delivered to the individual sources to therebyadjust the emission of heat from heating components 154 or 254 and 156or 256.

In order to achieve the activation temperature of the adhesive bead andyet reduce the assembly time, the shortwave and longwave infraredradiation is preferably applied for at least one minute but for lessthan about twenty minutes, more preferably, less than about ten, andmost preferably less than about five minutes. In preferred form, theshortwave and longwave infrared radiation is applied for less than abouttwo minutes. However, in order to accommodate the flow of the assemblyline conveyor, which for example may index or move a fixed distanceabout every 60 to about 90 seconds, the shortwave and longwave infraredradiation may be applied in stages. For example, where the total heatactivation time is about 3 to about 5 minutes and the conveyor indexesabout every 60 seconds, three or more stages would be required.Typically common, at least two heating stages are preferred. Mosttypically, four heating stages are preferred. Preferably, no more thanfour stages are used, although in some applications more than fourstages may be desirable, with each of the heating stages aligned alongthe conveyor to avoid any additional handling requirements and in closeproximity to the conveyor to avoid any cool down time. Optionally, asingle lear or heat tunnel may be used, through which the glass is movedon the conveyor. For example, a single lear or heat tunnel whichprovides either continuous heating or provides discrete heating regionsthat are continuously operated.

As an alternate to a conveyorized heater comprising a plurality ofheating stages arranged sequentially and with the glass substrates to beheated being loaded at a front stage and then passing through multipleheating stages to be unloaded at a rear stage (preferably with coolingprovided at the unload section at the rear stage), a system comprising aset of non-sequentially arranged heating stages, such as is illustratedin FIG. 16, can be used. Embodiment 405 comprises four individualheating stages, 410, 411, 412 and 413, clustered around a robot 415equipped with a robotic arm 416. Glass substrates, upon which a bead ofready-to-install adhesive has been dispensed about the substrateperiphery at a remote site distant from vehicle assembly line 420, arestaged in staging fixture 406. A one substrate onto which the adhesivehas been dispensed is picked up by robotic arm 416 and placed into anyvacant one of heating stages 410-413. While this one substrate is beingheated in the heating stage selected, another substrate, placedpreviously in another heating stage is unloaded by robotic arm 416 anddecked into the frame of automobile body 419 passing along vehicleassembly line 420. Once robot 415 has placed a substrate with a nowactivated window fixing adhesive into a vehicle body, robot 415 returnsto staging area 406 to pick up another substrate, and then move thissubstrate to the now vacant other heating stage. In this manner, asingle robot can be used to pick up substrates incoming from a remoteready-to-install adhesive application plant, place them in a discreteheating stage, and unload heated substrates for direct decking into thevehicle body. Each of discrete heating stages 410-413 can be equippedwith a cooling substage, can be provided with a heat localizer aspreviously described, and the entire operation can operate undercomputer control. Although illustrated in FIG. 16 with four heatingstages, a minimum of two stages is required and less than five stages ispreferred. Also, manual operations can substitute for some or all of therobotic operations of embodiment 405. The non-sequential multipleheating stage system of embodiment 405 has advantages in minimizingfloor space adjacent to the vehicle assembly line. Further, robotic arm416 can optionally be equipped with a bar code reader 417, or anequivalent part identifier reader, that reads a part identifier code oneach substrate in staging fixture 406, and determines whether thatparticular substrate is the correct substrate to sequence with a vehicleexpected to soon pass along the vehicle assembly line. In this manner,the manufacturing system illustrated in FIG. 16 can be adapted to suitjust-in-time, in sequence vehicle production, and it provides a measureof flexibility insofar that an out of sequence part can be temporarilyheld in a discrete heating stage until its intended vehicle body arrivesalong the vehicle assembly line. Optionally, staging fixture 406comprises a multi-substrate containing container which is loaded, mostpreferably, in-sequence to coordinate with the sequence of vehicles topass along vehicle assembly line 420, with multiple substrates at theremote ready-to-install facility. This container, which preferably is areturnable container as known in the automotive supply arts, serves as ashipping container for substrates to the vehicle assembly plant.

As described previously, the ready-to-install (RTI) heat activatableadhesive is preferably applied to the vehicle window at aready-to-install vehicle window facility that is remote from the vehicleassembly plant. The RTI adhesive is shipped to the vehicle assemblyplant in an uncured or partially cured form. Upon arrival at the vehicleassembly plant, and preferably immediately adjacent the vehicle assemblyline at the location where the windows are to be installed, the RTIadhesive is activated (most preferably by thermal activation althoughvarious forms of energy activation such as by microwave radiation,induction heating, and the like can be contemplated) to a state suitableto use as a window fixing adhesive for adhering the window to thevehicle body. Although described herein as a ready-to-install adhesive,this present invention contemplates that the adhesive as disposed on thesurface of the window substrate (or on a polymer gasket itself attachedto the vehicle window) can have a shape and form as applied with across-section that is square, rectangular, triangular, hemisphericaltrapezoidal, quadrilateral, bimodal, or the like and optionally with atip or apex portion that is narrower than the base that contacts thewindow substrate, and that it substantially retains that shape and formduring shipment from the RTI adhesive remote facility to the vehicleassembly plant where activation of the RTI adhesive will occur.

It is preferable that the RTI facility operate as a just-in-time (JIT)supplier of RTI windows to the vehicle assembly plant. Most preferably,the vehicle assembly plant is supplied from the RTI window plant usingjust-in-time, in-sequence techniques, such as are commonly known in theautomotive supply arts, and such as are commonly used such as to supplyseats to vehicles. In such a process, the assembly plant contacts theRTI window facility at the moment a specific vehicle body passes alocation on the assembly line (such as entering or exiting the paintshop). The vehicle maker places a specific order for a window (or windowset such as a front windshield and a rear backlite) for that particularvehicle, and for those that preceded and followed that particularvehicle on the assembly line. Thus the ready-to-install window receivesorders from the vehicle assembly plant for just-in-time delivery and,preferably, in-sequence delivery. The time window for fabrication of theRTI windows at the RTI window plant and/or their delivery to the vehicleassembly plant is at least about two hours, more preferably is at leastabout three hours, and most preferably is at least about four hours, andis less than about forty eight hours, more preferably is less than abouttwenty four hours and most preferably is less than about twelve hours.For example, a preferred time window for JIT/in-sequence supply isbetween three to nine hours after an order is received at the RTI windowplant. Within this time window, the RTI window facility fabricatesand/or ships a RTI window, or set of windows, for JIT receipt at thevehicle assembly line, and more preferably, for installation ,in-sequence, at the vehicle assembly line. In this regard and in orderto allow sufficient RTI window fabrication and/or shipping time forJIT/in-sequence supply to the vehicle assembly plant, it is preferablethat the RTI window plant be located remote from, but close to, thevehicle assembly line (less than about 60 miles distance desired, lessthan about 30 miles more desirable, and less than about 15 miles mostdesirable). Most preferably, the RTI window production line would belocated at or within the vehicle assembly plant itself, whereupon, thetime window for RTI window fabrication and supply to the assembly linecan be less than about two hours. Alternately, the RTI window productionline could be located at a vehicle window fabrication facility such aswithin a glass vehicle window fabrication plant.

At the RTI window plant the RTI adhesive can be disposed onto the windowsubstrate (such as about the perimeter of a glass windshield) by avariety of means. For example, it can be dispensed from a robotic armmounted dispenser head. Preferably, the dispenser head is capable ofproviding a variable profile adhesive bead. Alternately, the RTIadhesive can be dispensed into a mold separate from the panel, with themold locating the panel on the adhesive. With the RTI adhesive in themold, the panel is located on the adhesive and these are forced togetherso that the RTI adhesive bead is transferred from its mold to the windowpanel, whereupon the panel, with RTI adhesive applied thereto, isshipped to the vehicle assembly plant, such as is described in U.S. Pat.No. 5,331,784 entitled VEHICULAR PANEL ASSEMBLY AND METHOD FOR MAKINGSAME assigned to Donnelly Corporation of Holland, Mich., which isincorporated herein by reference in its entirety.

Accordingly, the invention provides a heater assembly and method usefulin installing panel assemblies, including modular window assemblies,with a heat activated adhesive that permits quick installation withoutthe manufacturing, handling, storage, and cleaning problems associatedwith the moisture cure adhesives used heretofore. The invention allows apanel assembly to be preassembled with the adhesive pre-applied and yetnot activated until the panel assembly is ready to install. Further, theinvention provides for a method of coding the heated panel withoutinterfering with the heat activation of the bead of adhesive.

For the purposes of the following description, the terms “upper,”“lower,” “vertical,” and derivatives or equivalents thereof shall relateto the invention as oriented in FIGS. 1 to 12. It is understood that theinvention may assume various alternative orientations, except whereexpressly specified to the contrary. For example, where panel assembly10 or 10′ is inverted, first and second heating components 54, 56, 154,and 156 may be reversed so that first heating components 54, 154 ispositioned below panel assembly 10, 10′ and second heater assembly 56,156 is positioned above panel assembly 10, 10′. Furthermore, the numberof heaters or stage heaters may be varied depending on the conveyorspeed. Moreover, heaters 50, 150, and 250 may assume differentarrangements for supporting the infrared radiation sources. It is alsounderstood that the specific devices and methods illustrated in theattached drawings, and described in the following specification, aresimply exemplary embodiments of the inventive concepts defined in theappended claims. Further, while some forms of the invention have beenshown and described, other forms will now be apparent to those skilledin the art. Therefore, it will be understood that the embodiment shownin the drawing and described above are merely for illustrative purposes,are not intended to limit the scope of the invention which is defined bythe claims which follow at the end of the description.

We claim:
 1. A method of preparing a vehicle panel assembly forattaching the panel assembly to a vehicle, the vehicle panel assemblyhaving a substrate and a bead of ready-to-install heat activatedadhesive, the substrate having first and second sides and a peripheralportion, the bead being applied to the second side of the substrate andincluding a central core portion, an outer skin portion, and aninterface portion on the second side of the substrate, said methodcomprising the steps of: heating the first side of the substrate wherebythe substrate heats the interface portion of the bead to heat thecentral core portion of the bead; heating the outer skin portion of thebead thereby heating the central core portion of the bead and activatingthe ready-to-install heat activated adhesive; and cooling the substrateafter heating to permit manual handling of the panel assembly after theadhesive is heat activated.
 2. The method of preparing a vehicle panelassembly according to claim 1, wherein cooling includes directing agaseous stream to the peripheral portion of the substrate to cool thesubstrate to permit handling of the vehicle panel assembly.
 3. Themethod of preparing a vehicle panel assembly according to claim 2,wherein directing includes blowing one of air and an inert gas onto theperipheral portion of the substrate to thereby cool the substrate. 4.The method of preparing a vehicle panel assembly according to claim 3,wherein blowing includes blowing said one of air and an inert gas ontothe peripheral portion at an angle in a range of approximately 0° to 85°from a central axis of the bead.
 5. The method of preparing a vehiclepanel assembly according to claim 2, wherein directing a gaseous streamincludes localizing the gaseous stream on a peripheral portion of thesubstrate to cool the substrate.
 6. The method of preparing a vehiclepanel assembly according to claim 5, wherein localizing includes blowingthe gaseous stream on the peripheral portion with a knife edge blower.7. The method of preparing a vehicle panel assembly according to claim1, further comprising balancing the heating and the cooling to ensurethat the central core portion at least reaches its heat activationtemperature while cooling the substrate below 250° F. within a period ofless than fifteen minutes after heating.
 8. The method of preparing avehicle panel assembly according to claim 7, wherein balancing includesheating the central core portion of the bead to at least a heatactivated temperature in a range of 5 seconds to 10 minutes and coolingthe substrate temperature below 120° F. within a period of about twominutes after heating.
 9. The method of preparing a vehicle panelassembly according to claim 1, further comprising balancing the heat onthe first side and the heat on the second side to heat the central coreportion to at least a heat activation temperature in a range of about50° C. to 160° C. while maintaining an outer skin surface temperature atleast no more than about 40° C. greater than the central core portiontemperature and cooling the substrate temperature below 120° F. within aperiod of less than fifteen minutes after heating.
 10. The method ofpreparing a vehicle panel assembly according to claim 1, wherein heatingthe first side of the substrate includes heating with shortwave infraredradiation.
 11. The method of preparing a vehicle panel assemblyaccording to claim 1, wherein heating the outer skin portion includesheating with longwave infrared radiation.
 12. The method of preparing avehicle panel assembly according to claim 11, wherein heating withlongwave infrared radiation includes heating with a thermal masstemperature in a range of about 450° F. to 900° F.
 13. The method ofpreparing a vehicle panel assembly according to claim 12, wherein saidheating with longwave infrared radiation includes heating with a thermalmass temperature in a range of about 500° F. to 750° F.
 14. The methodof preparing a vehicle panel assembly according to claim 11, whereincooling includes initiating the cooling after the adhesive has reached aheat activation temperature.
 15. The method of preparing a vehicle panelassembly according to claim 14, wherein cooling includes directing airto the peripheral portion of the substrate.
 16. The method of preparinga vehicle panel assembly according to claim 15, wherein directingincludes blowing air onto the peripheral portion of the substrate. 17.The method of preparing a vehicle panel assembly according to claim 16,wherein blowing air includes localizing the air on the peripheralportion of the substrate.
 18. The method of preparing a vehicle panelassembly according to claim 15, wherein heating the first side of thesubstrate includes heating with shortwave infrared radiation.
 19. Themethod of preparing a vehicle panel assembly according to claim 18,wherein heating with shortwave infrared radiation includes heating withshortwave radiation having a peak emission of less than about 2.5microns.
 20. The method of preparing a vehicle panel assembly accordingto claim 18, further comprising directing the shortwave infraredradiation onto a portion of the substrate on the first side of thesubstrate aligned with the bead.
 21. The method of preparing a vehiclepanel assembly according to claim 15, wherein heating the outer skin ofportion of the bead includes localizing the heating on the outer skinportion of the bead.
 22. The method of preparing a vehicle panelassembly according to claim 21, wherein heating with longwave infraredradiation includes heating with a thermal mass in a range of about 450°F. to 900° F.
 23. The method of preparing a vehicle panel assemblyaccording to claim 14, further comprising balancing the cooling and theheating whereby the bead is heated to its heat activation temperatureand the substrate of the vehicle panel is cooled to a temperature below250° F. within a period of less than fifteen minutes after the coreportion reaches the heat activation temperature.
 24. The method ofpreparing a vehicle panel assembly according to claim 1, furtherincluding initiating the cooling within a range of about 0 to 5 minutesafter heating.
 25. The method of preparing a vehicle panel assemblyaccording to claim 1, wherein heating the first side of the substrateand heating the outer skin portion of the bead are substantiallysimultaneous.
 26. The method of preparing a vehicle panel assemblyaccording to claim 1, wherein one of heating the first side of thesubstrate and heating the outer skin portion of the bead is initiatedafter the other of the heating the first side of the panel and heatingthe outer skin of the bead.
 27. The method of preparing a vehicle panelassembly according to claim 1, wherein heating the outer skin portionincludes localizing heat on the bead of ready-to-install heat activatedadhesive.
 28. The method of preparing a vehicle panel assembly accordingto claim 27, whereby localizing includes providing a heat localizerhaving reflective sides, said reflective sides directing the heat on thebead.
 29. The method of preparing a vehicle panel assembly according toclaim 1, wherein heating the first side includes heating a portion ofthe first side of the substrate aligned with the bead.
 30. The method ofpreparing a vehicle panel assembly according to claim 1, wherein thesubstrate includes a gasket, and heating the first side includes heatinga portion of the first side of the substrate offset from the bead, theportion being adjacent the gasket.
 31. The method of preparing a vehiclepanel assembly for attaching the vehicle panel assembly to a vehicle,the vehicle panel assembly having a substrate and a bead of the heatactivated adhesive, the substrate having first and second sides and aperipheral portion, the peripheral portion including a gasket formedthereon, the gasket extending over at least a portion of the second sideof the substrate, and the bead of ready-to-install heat activatedadhesive being applied to the gasket, the bead including an interfaceportion on the gasket, a central core portion, and an outer skinportion, said method comprising the steps of: heating the first side ofthe substrate adjacent the gasket whereby the substrate heats the gasketto heat the interface portion of the bead; and heating the outer skinportion of the bead to thereby heat the central core portion of the beadand activate the ready-to-install heat activated adhesive.
 32. Themethod of preparing a vehicle panel assembly according to claim 31,further comprising cooling the substrate after heating the first side ofthe substrate and heating the outer skin portion of the bead.
 33. Themethod of preparing a vehicle panel assembly according to claim 32,wherein cooling includes cooling the substrate after theready-to-install heat activated adhesive is activated.
 34. The method ofpreparing a vehicle panel assembly according to claim 32, whereincooling includes cooling the substrate within a range of about 0 to 5minutes after heating the first side of the substrate and heating theouter skin portion of the bead.
 35. The method of preparing a vehiclepanel assembly according to claim 32, wherein cooling includes directingair onto the substrate to cool the substrate.
 36. The method ofpreparing a vehicle panel assembly according to claim 35, whereindirecting air includes directing air onto the peripheral portion of thesubstrate.
 37. The method of preparing a vehicle panel assemblyaccording to claim 36, wherein directing air onto the peripheral portionincludes directing air onto the peripheral portion at an angle in arange of approximately 0° to 85° from a central axis of the bead. 38.The method of preparing a vehicle panel assembly according to claim 32,wherein cooling includes blowing air with one of an air knife air blowerassembly and a turbo fan.
 39. The method of preparing a vehicle panelassembly according to claim 32, wherein cooling includes cooling thesubstrate to a temperature of 120° F. or less within a period of twominutes or less after heating.
 40. The method of preparing a vehiclepanel assembly according to claim 31, wherein heating the first side ofthe substrate includes directing the heat onto a portion being offsetfrom the bead of adhesive.
 41. The method of preparing a vehicle panelassembly according to claim 40, wherein heating the outer skin portionof the bead includes localizing the heat on the bead to protect thegasket from the heat.
 42. The method of preparing a vehicle panelassembly according to claim 31, wherein heating at least a portion ofthe first side includes heating with shortwave infrared radiation. 43.The method of preparing a vehicle panel assembly according to claim 42,wherein heating the outer skin portion includes heating with longwaveinfrared radiation.
 44. A method of preparing a vehicle panel assemblyfor attaching to a vehicle, the vehicle panel assembly having asubstrate and a bead of ready-to-install heat activated adhesive, thesubstrate including first and second sides and a peripheral portion, andthe bead being provided on the second side of the substrate andincluding a central core portion, an outer skin portion and an interfaceportion on the second side of the substrate, said method comprising thesteps of: heating the substrate with a shortwave radiation sourcethereby heating the bead with the substrate through the interfaceportion of the bead; heating the bead with a source of longwave infraredradiation whereby the core of the bead at least reaches an activationtemperature; and cooling the substrate after heating the bead therebypermitting handling of the vehicle panel assembly after the bead ofadhesive is activated.
 45. The method of preparing a vehicle panelassembly according to claim 44, further comprising balancing the heatingand the cooling such that the core of the bead of adhesive reaches itsactivation temperature and the substrate is cooled to a temperature of120° F. or less within a period of five minutes or less after heating.46. The method of preparing a vehicle panel assembly according to claim45, wherein heating the substrate includes localizing the heat from theshortwave infrared radiation source onto a portion of the first side ofthe substrate.
 47. The method of preparing a vehicle panel assemblyaccording to claim 44, wherein heating the bead includes localizing theheat from the longwave infrared radiation source onto the outer skinportion of the bead.
 48. The method of preparing a vehicle panelassembly according to claim 44, wherein cooling includes blowing agaseous stream onto the peripheral portion of the substrate.
 49. Themethod of preparing a vehicle panel assembly according to claim 44,further comprising initiating the cooling within five minutes or lessafter heating.
 50. The method of preparing a vehicle panel assemblyaccording to claim 44, further comprising initiating the cooling withinfive minutes or less of the core portion of the bead reaching itsactivation temperature.
 51. The method of preparing a vehicle panelassembly according to claim 46, wherein localizing includes localizingthe heat on a portion of the first side of the substrate which isgenerally aligned with the bead.
 52. The method of preparing a vehiclepanel assembly according to claim 44, wherein heating the substrateincludes positioning at least one heating lamp spaced from the firstside of the substrate over the portion of the substrate and aligning thelamp with a central axis of the bead.
 53. The method of preparing avehicle panel assembly according to claim 52, wherein positioningincludes spacing the lamp at a distance of less than twenty-four inchesfrom the first side of the substrate.
 54. The method of preparing avehicle panel assembly according to claim 44, wherein heating the beadincludes positioning the source of longwave radiation spaced from thesecond side of the substrate.
 55. The method of preparing a vehiclepanel assembly according to claim 54, wherein positioning includesspacing the source of longwave infrared radiation less than abouttwenty-four inches from the second side of the substrate.
 56. The methodof preparing a vehicle panel assembly according to claim 44, whereinsaid heating the substrate and heating the bead is substantiallysimultaneous.